There are a variety of types of physical barriers that have been used as release agents in the spark plug-to-spark plug boot interface in automotive applications. The two primary purposes of the physical barrier are to improve the dielectric capability of the interface and to prevent the spark plug and spark plug boot from bonding to each other. Heretofore, greases and powders have been put in the boots, and fluorotelomer coatings have been put on spark plugs. However, such techniques do not meet desired characteristics for a superior release agent. Preferably, the desired characteristics of a superior release agent are as follows:
1) provide excellent dielectric capability; PA1 2) prevent spark plug-to-spark plug boot bonding; PA1 3) sustain acceptable engage/disengage forces for the interface; PA1 4) insure no detrimental physical or chemical effects on the interface components; PA1 5) remain operable after elevated temperatures and environmental exposures; PA1 6) process easily and readily; and PA1 7) are cost effective.
Prior spark plug boot greases do not meet the above-cited characteristics for one reason or another. Some greases tend to dry up and fall out of the interface over a period of time resulting in poor dielectric and mechanical properties. Powders often have higher than desired mechanical properties. Plug coatings, such as fluorotelomer, are usually much too expensive to be commercially utilized in automotive applications.
The present invention overcomes the shortcomings of the prior art spark plug boot and spark plug lubricant technology.